forked from luck/tmp_suning_uos_patched
tty: bfin_jtag_comm: emulate a TTY over the Blackfin EMUDAT/JTAG interface
The Blackfin JTAG interface has a 4 byte generic data field (EMUDAT). With a little creative thinking, we can turn this into a TTY device. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Bryan Wu <cooloney@kernel.org> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Frysinger
Linus Torvalds
parent
7e9cd3a617
commit
0b91421857
@ -97,6 +97,19 @@ config DEVKMEM
|
||||
kind of kernel debugging operations.
|
||||
When in doubt, say "N".
|
||||
|
||||
config BFIN_JTAG_COMM
|
||||
tristate "Blackfin JTAG Communication"
|
||||
depends on BLACKFIN
|
||||
help
|
||||
Add support for emulating a TTY device over the Blackfin JTAG.
|
||||
|
||||
To compile this driver as a module, choose M here: the
|
||||
module will be called bfin_jtag_comm.
|
||||
|
||||
config BFIN_JTAG_COMM_CONSOLE
|
||||
bool "Console on Blackfin JTAG"
|
||||
depends on BFIN_JTAG_COMM=y
|
||||
|
||||
config SERIAL_NONSTANDARD
|
||||
bool "Non-standard serial port support"
|
||||
depends on HAS_IOMEM
|
||||
|
||||
@ -13,6 +13,7 @@ obj-$(CONFIG_LEGACY_PTYS) += pty.o
|
||||
obj-$(CONFIG_UNIX98_PTYS) += pty.o
|
||||
obj-y += misc.o
|
||||
obj-$(CONFIG_VT) += vt_ioctl.o vc_screen.o selection.o keyboard.o
|
||||
obj-$(CONFIG_BFIN_JTAG_COMM) += bfin_jtag_comm.o
|
||||
obj-$(CONFIG_CONSOLE_TRANSLATIONS) += consolemap.o consolemap_deftbl.o
|
||||
obj-$(CONFIG_HW_CONSOLE) += vt.o defkeymap.o
|
||||
obj-$(CONFIG_AUDIT) += tty_audit.o
|
||||
|
||||
365
drivers/char/bfin_jtag_comm.c
Normal file
365
drivers/char/bfin_jtag_comm.c
Normal file
@ -0,0 +1,365 @@
|
||||
/*
|
||||
* TTY over Blackfin JTAG Communication
|
||||
*
|
||||
* Copyright 2008-2009 Analog Devices Inc.
|
||||
*
|
||||
* Enter bugs at http://blackfin.uclinux.org/
|
||||
*
|
||||
* Licensed under the GPL-2 or later.
|
||||
*/
|
||||
|
||||
#include <linux/circ_buf.h>
|
||||
#include <linux/console.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/err.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/kthread.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/mutex.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/tty.h>
|
||||
#include <linux/tty_driver.h>
|
||||
#include <linux/tty_flip.h>
|
||||
#include <asm/atomic.h>
|
||||
|
||||
/* See the Debug/Emulation chapter in the HRM */
|
||||
#define EMUDOF 0x00000001 /* EMUDAT_OUT full & valid */
|
||||
#define EMUDIF 0x00000002 /* EMUDAT_IN full & valid */
|
||||
#define EMUDOOVF 0x00000004 /* EMUDAT_OUT overflow */
|
||||
#define EMUDIOVF 0x00000008 /* EMUDAT_IN overflow */
|
||||
|
||||
#define DRV_NAME "bfin-jtag-comm"
|
||||
#define DEV_NAME "ttyBFJC"
|
||||
|
||||
#define pr_init(fmt, args...) ({ static const __initdata char __fmt[] = fmt; printk(__fmt, ## args); })
|
||||
#define debug(fmt, args...) pr_debug(DRV_NAME ": " fmt, ## args)
|
||||
|
||||
static inline uint32_t bfin_write_emudat(uint32_t emudat)
|
||||
{
|
||||
__asm__ __volatile__("emudat = %0;" : : "d"(emudat));
|
||||
return emudat;
|
||||
}
|
||||
|
||||
static inline uint32_t bfin_read_emudat(void)
|
||||
{
|
||||
uint32_t emudat;
|
||||
__asm__ __volatile__("%0 = emudat;" : "=d"(emudat));
|
||||
return emudat;
|
||||
}
|
||||
|
||||
static inline uint32_t bfin_write_emudat_chars(char a, char b, char c, char d)
|
||||
{
|
||||
return bfin_write_emudat((a << 0) | (b << 8) | (c << 16) | (d << 24));
|
||||
}
|
||||
|
||||
#define CIRC_SIZE 2048 /* see comment in tty_io.c:do_tty_write() */
|
||||
#define CIRC_MASK (CIRC_SIZE - 1)
|
||||
#define circ_empty(circ) ((circ)->head == (circ)->tail)
|
||||
#define circ_free(circ) CIRC_SPACE((circ)->head, (circ)->tail, CIRC_SIZE)
|
||||
#define circ_cnt(circ) CIRC_CNT((circ)->head, (circ)->tail, CIRC_SIZE)
|
||||
#define circ_byte(circ, idx) ((circ)->buf[(idx) & CIRC_MASK])
|
||||
|
||||
static struct tty_driver *bfin_jc_driver;
|
||||
static struct task_struct *bfin_jc_kthread;
|
||||
static struct tty_struct * volatile bfin_jc_tty;
|
||||
static unsigned long bfin_jc_count;
|
||||
static DEFINE_MUTEX(bfin_jc_tty_mutex);
|
||||
static volatile struct circ_buf bfin_jc_write_buf;
|
||||
|
||||
static int
|
||||
bfin_jc_emudat_manager(void *arg)
|
||||
{
|
||||
uint32_t inbound_len = 0, outbound_len = 0;
|
||||
|
||||
while (!kthread_should_stop()) {
|
||||
/* no one left to give data to, so sleep */
|
||||
if (bfin_jc_tty == NULL && circ_empty(&bfin_jc_write_buf)) {
|
||||
debug("waiting for readers\n");
|
||||
__set_current_state(TASK_UNINTERRUPTIBLE);
|
||||
schedule();
|
||||
__set_current_state(TASK_RUNNING);
|
||||
}
|
||||
|
||||
/* no data available, so just chill */
|
||||
if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) {
|
||||
debug("waiting for data (in_len = %i) (circ: %i %i)\n",
|
||||
inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head);
|
||||
if (inbound_len)
|
||||
schedule();
|
||||
else
|
||||
schedule_timeout_interruptible(HZ);
|
||||
continue;
|
||||
}
|
||||
|
||||
/* if incoming data is ready, eat it */
|
||||
if (bfin_read_DBGSTAT() & EMUDIF) {
|
||||
struct tty_struct *tty;
|
||||
mutex_lock(&bfin_jc_tty_mutex);
|
||||
tty = (struct tty_struct *)bfin_jc_tty;
|
||||
if (tty != NULL) {
|
||||
uint32_t emudat = bfin_read_emudat();
|
||||
if (inbound_len == 0) {
|
||||
debug("incoming length: 0x%08x\n", emudat);
|
||||
inbound_len = emudat;
|
||||
} else {
|
||||
size_t num_chars = (4 <= inbound_len ? 4 : inbound_len);
|
||||
debug(" incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars);
|
||||
inbound_len -= num_chars;
|
||||
tty_insert_flip_string(tty, (unsigned char *)&emudat, num_chars);
|
||||
tty_flip_buffer_push(tty);
|
||||
}
|
||||
}
|
||||
mutex_unlock(&bfin_jc_tty_mutex);
|
||||
}
|
||||
|
||||
/* if outgoing data is ready, post it */
|
||||
if (!(bfin_read_DBGSTAT() & EMUDOF) && !circ_empty(&bfin_jc_write_buf)) {
|
||||
if (outbound_len == 0) {
|
||||
outbound_len = circ_cnt(&bfin_jc_write_buf);
|
||||
bfin_write_emudat(outbound_len);
|
||||
debug("outgoing length: 0x%08x\n", outbound_len);
|
||||
} else {
|
||||
struct tty_struct *tty;
|
||||
int tail = bfin_jc_write_buf.tail;
|
||||
size_t ate = (4 <= outbound_len ? 4 : outbound_len);
|
||||
uint32_t emudat =
|
||||
bfin_write_emudat_chars(
|
||||
circ_byte(&bfin_jc_write_buf, tail + 0),
|
||||
circ_byte(&bfin_jc_write_buf, tail + 1),
|
||||
circ_byte(&bfin_jc_write_buf, tail + 2),
|
||||
circ_byte(&bfin_jc_write_buf, tail + 3)
|
||||
);
|
||||
bfin_jc_write_buf.tail += ate;
|
||||
outbound_len -= ate;
|
||||
mutex_lock(&bfin_jc_tty_mutex);
|
||||
tty = (struct tty_struct *)bfin_jc_tty;
|
||||
if (tty)
|
||||
tty_wakeup(tty);
|
||||
mutex_unlock(&bfin_jc_tty_mutex);
|
||||
debug(" outgoing data: 0x%08x (pushing %zu)\n", emudat, ate);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
__set_current_state(TASK_RUNNING);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int
|
||||
bfin_jc_open(struct tty_struct *tty, struct file *filp)
|
||||
{
|
||||
mutex_lock(&bfin_jc_tty_mutex);
|
||||
debug("open %lu\n", bfin_jc_count);
|
||||
++bfin_jc_count;
|
||||
bfin_jc_tty = tty;
|
||||
wake_up_process(bfin_jc_kthread);
|
||||
mutex_unlock(&bfin_jc_tty_mutex);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void
|
||||
bfin_jc_close(struct tty_struct *tty, struct file *filp)
|
||||
{
|
||||
mutex_lock(&bfin_jc_tty_mutex);
|
||||
debug("close %lu\n", bfin_jc_count);
|
||||
if (--bfin_jc_count == 0)
|
||||
bfin_jc_tty = NULL;
|
||||
wake_up_process(bfin_jc_kthread);
|
||||
mutex_unlock(&bfin_jc_tty_mutex);
|
||||
}
|
||||
|
||||
/* XXX: we dont handle the put_char() case where we must handle count = 1 */
|
||||
static int
|
||||
bfin_jc_circ_write(const unsigned char *buf, int count)
|
||||
{
|
||||
int i;
|
||||
count = min(count, circ_free(&bfin_jc_write_buf));
|
||||
debug("going to write chunk of %i bytes\n", count);
|
||||
for (i = 0; i < count; ++i)
|
||||
circ_byte(&bfin_jc_write_buf, bfin_jc_write_buf.head + i) = buf[i];
|
||||
bfin_jc_write_buf.head += i;
|
||||
return i;
|
||||
}
|
||||
|
||||
#ifndef CONFIG_BFIN_JTAG_COMM_CONSOLE
|
||||
# define acquire_console_sem()
|
||||
# define release_console_sem()
|
||||
#endif
|
||||
static int
|
||||
bfin_jc_write(struct tty_struct *tty, const unsigned char *buf, int count)
|
||||
{
|
||||
int i;
|
||||
acquire_console_sem();
|
||||
i = bfin_jc_circ_write(buf, count);
|
||||
release_console_sem();
|
||||
wake_up_process(bfin_jc_kthread);
|
||||
return i;
|
||||
}
|
||||
|
||||
static void
|
||||
bfin_jc_flush_chars(struct tty_struct *tty)
|
||||
{
|
||||
wake_up_process(bfin_jc_kthread);
|
||||
}
|
||||
|
||||
static int
|
||||
bfin_jc_write_room(struct tty_struct *tty)
|
||||
{
|
||||
return circ_free(&bfin_jc_write_buf);
|
||||
}
|
||||
|
||||
static int
|
||||
bfin_jc_chars_in_buffer(struct tty_struct *tty)
|
||||
{
|
||||
return circ_cnt(&bfin_jc_write_buf);
|
||||
}
|
||||
|
||||
static void
|
||||
bfin_jc_wait_until_sent(struct tty_struct *tty, int timeout)
|
||||
{
|
||||
unsigned long expire = jiffies + timeout;
|
||||
while (!circ_empty(&bfin_jc_write_buf)) {
|
||||
if (signal_pending(current))
|
||||
break;
|
||||
if (time_after(jiffies, expire))
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
static struct tty_operations bfin_jc_ops = {
|
||||
.open = bfin_jc_open,
|
||||
.close = bfin_jc_close,
|
||||
.write = bfin_jc_write,
|
||||
/*.put_char = bfin_jc_put_char,*/
|
||||
.flush_chars = bfin_jc_flush_chars,
|
||||
.write_room = bfin_jc_write_room,
|
||||
.chars_in_buffer = bfin_jc_chars_in_buffer,
|
||||
.wait_until_sent = bfin_jc_wait_until_sent,
|
||||
};
|
||||
|
||||
static int __init bfin_jc_init(void)
|
||||
{
|
||||
int ret;
|
||||
|
||||
bfin_jc_kthread = kthread_create(bfin_jc_emudat_manager, NULL, DRV_NAME);
|
||||
if (IS_ERR(bfin_jc_kthread))
|
||||
return PTR_ERR(bfin_jc_kthread);
|
||||
|
||||
ret = -ENOMEM;
|
||||
|
||||
bfin_jc_write_buf.head = bfin_jc_write_buf.tail = 0;
|
||||
bfin_jc_write_buf.buf = kmalloc(CIRC_SIZE, GFP_KERNEL);
|
||||
if (!bfin_jc_write_buf.buf)
|
||||
goto err;
|
||||
|
||||
bfin_jc_driver = alloc_tty_driver(1);
|
||||
if (!bfin_jc_driver)
|
||||
goto err;
|
||||
|
||||
bfin_jc_driver->owner = THIS_MODULE;
|
||||
bfin_jc_driver->driver_name = DRV_NAME;
|
||||
bfin_jc_driver->name = DEV_NAME;
|
||||
bfin_jc_driver->type = TTY_DRIVER_TYPE_SERIAL;
|
||||
bfin_jc_driver->subtype = SERIAL_TYPE_NORMAL;
|
||||
bfin_jc_driver->init_termios = tty_std_termios;
|
||||
tty_set_operations(bfin_jc_driver, &bfin_jc_ops);
|
||||
|
||||
ret = tty_register_driver(bfin_jc_driver);
|
||||
if (ret)
|
||||
goto err;
|
||||
|
||||
pr_init(KERN_INFO DRV_NAME ": initialized\n");
|
||||
|
||||
return 0;
|
||||
|
||||
err:
|
||||
put_tty_driver(bfin_jc_driver);
|
||||
kfree(bfin_jc_write_buf.buf);
|
||||
kthread_stop(bfin_jc_kthread);
|
||||
return ret;
|
||||
}
|
||||
module_init(bfin_jc_init);
|
||||
|
||||
static void __exit bfin_jc_exit(void)
|
||||
{
|
||||
kthread_stop(bfin_jc_kthread);
|
||||
kfree(bfin_jc_write_buf.buf);
|
||||
tty_unregister_driver(bfin_jc_driver);
|
||||
put_tty_driver(bfin_jc_driver);
|
||||
}
|
||||
module_exit(bfin_jc_exit);
|
||||
|
||||
#if defined(CONFIG_BFIN_JTAG_COMM_CONSOLE) || defined(CONFIG_EARLY_PRINTK)
|
||||
static void
|
||||
bfin_jc_straight_buffer_write(const char *buf, unsigned count)
|
||||
{
|
||||
unsigned ate = 0;
|
||||
while (bfin_read_DBGSTAT() & EMUDOF)
|
||||
continue;
|
||||
bfin_write_emudat(count);
|
||||
while (ate < count) {
|
||||
while (bfin_read_DBGSTAT() & EMUDOF)
|
||||
continue;
|
||||
bfin_write_emudat_chars(buf[ate], buf[ate+1], buf[ate+2], buf[ate+3]);
|
||||
ate += 4;
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_BFIN_JTAG_COMM_CONSOLE
|
||||
static void
|
||||
bfin_jc_console_write(struct console *co, const char *buf, unsigned count)
|
||||
{
|
||||
if (bfin_jc_kthread == NULL)
|
||||
bfin_jc_straight_buffer_write(buf, count);
|
||||
else
|
||||
bfin_jc_circ_write(buf, count);
|
||||
}
|
||||
|
||||
static struct tty_driver *
|
||||
bfin_jc_console_device(struct console *co, int *index)
|
||||
{
|
||||
*index = co->index;
|
||||
return bfin_jc_driver;
|
||||
}
|
||||
|
||||
static struct console bfin_jc_console = {
|
||||
.name = DEV_NAME,
|
||||
.write = bfin_jc_console_write,
|
||||
.device = bfin_jc_console_device,
|
||||
.flags = CON_ANYTIME | CON_PRINTBUFFER,
|
||||
.index = -1,
|
||||
};
|
||||
|
||||
static int __init bfin_jc_console_init(void)
|
||||
{
|
||||
register_console(&bfin_jc_console);
|
||||
return 0;
|
||||
}
|
||||
console_initcall(bfin_jc_console_init);
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_EARLY_PRINTK
|
||||
static void __init
|
||||
bfin_jc_early_write(struct console *co, const char *buf, unsigned int count)
|
||||
{
|
||||
bfin_jc_straight_buffer_write(buf, count);
|
||||
}
|
||||
|
||||
static struct __initdata console bfin_jc_early_console = {
|
||||
.name = "early_BFJC",
|
||||
.write = bfin_jc_early_write,
|
||||
.flags = CON_ANYTIME | CON_PRINTBUFFER,
|
||||
.index = -1,
|
||||
};
|
||||
|
||||
struct console * __init
|
||||
bfin_jc_early_init(unsigned int port, unsigned int cflag)
|
||||
{
|
||||
return &bfin_jc_early_console;
|
||||
}
|
||||
#endif
|
||||
|
||||
MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
|
||||
MODULE_DESCRIPTION("TTY over Blackfin JTAG Communication");
|
||||
MODULE_LICENSE("GPL");
|
||||
Loading…
Reference in New Issue
Block a user